The main goal is to provide all the information necessary for someone else to repeat your experiment and obtain similar results
Schematics of how to hook up the instruments
Product numbers and manufacturers / lot numbers if perishable material
Description of experimental technique (how did you twist the dial; what were criteria for "center of spectral line" or "starting / stopping stopwatch?" or "pumping the oil droplets")
Pictures of instruments great -- you can use PowerPoint or something to add arrows and text to these photos if you want